The present invention relates in general to couplings for rotatable mechanical members and in particular to a quick disconnect mechanism for selectively connecting a journal shaft to an end yoke of a power take-off for rotation therewith.
Tractors and other heavy machinery have long been utilized to tow agricultural implements, while simultaneously providing motive power thereto. Typically, a power take-off connected to the tractor engine is provided at the rear of the tractor for supplying rotational motive power to a journal shaft of the agricultural implement. The power take-off is usually provided with a universal joint coupling to accommodate movement of the journal shaft. The output of the universal joint is an end yoke hub having a longitudinal passageway formed therethrough. The passageway is formed co-axially with respect to the axis of rotation of the hub. The journal shaft is adapted to be inserted longitudinally within the hub passageway. The interior of the hub and the exterior of the journal shaft are splined or squared in complementary fashion such that they rotate as a unit when the journal shaft is inserted within the hub. A locking device of some sort is usually required to prevent the journal shaft from being longitudinally withdrawn from the hub during use.
It is well known to provide a releasable coupling between such a hub and journal shaft assembly which permits selective disconnection thereof in a rapid and safe manner without the use of tools. Such a coupling usually includes an aperture formed through the hub in a direction which is generally perpendicular to the longitudinal axis of the hub. The aperture is located such that it extends at least partially through the hub passageway into the space normally occupied by the journal shaft. A locking pin is slidably disposed in the aperture. The journal shaft is provided with a groove in the exterior surface thereof to receive the pin therein. When the pin is inserted through the aperture formed through the hub and through the groove formed through the journal shaft, it prevents the removal of the journal shaft from the hub. The pin includes a recessed portion which, when aligned with the groove, permits the journal shaft to be removed from the hub without completely withdrawing the pin from the aperture. A spring is often provided to urge the pin to a position wherein the recess therein is not aligned with the journal shaft groove, thus normally preventing the removal of the journal shaft from the hub. Such designs often provide that a portion of the slidable locking pin extend outwardly from the hub inclined (relative to the radii of the hub and journal shaft) in a direction toward the direction of rotation of the hub and journal shaft during use.